<?php
/*
 * Copyright 2010 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
/**
 * This class implements the RESTful transport of apiServiceRequest()'s
 *
 * @author Chris Chabot <chabotc@google.com>
 * @author Chirag Shah <chirags@google.com>
 */
class Google_REST
{
    /**
   * Executes a apiServiceRequest using a RESTful call by transforming it into
   * an apiHttpRequest, and executed via apiIO::authenticatedRequest().
   *
   * @param Google_HttpRequest $req
   * @return array decoded result
   * @throws Google_ServiceException on server side error (ie: not authenticated,
   *  invalid or malformed post body, invalid url)
   */
  public static function execute(Google_HttpRequest $req)
  {
      $httpRequest = Google_Client::$io->makeRequest($req);
      $decodedResponse = self::decodeHttpResponse($httpRequest);
      $ret = isset($decodedResponse['data'])
        ? $decodedResponse['data'] : $decodedResponse;

      return $ret;
  }

  /**
   * Decode an HTTP Response.
   * @static
   * @throws Google_ServiceException
   * @param Google_HttpRequest $response The http response to be decoded.
   * @return mixed|null
   */
  public static function decodeHttpResponse($response)
  {
      $code = $response->getResponseHttpCode();
      $body = $response->getResponseBody();
      $decoded = null;

      if ($code != '200' && $code != '201' && $code != '204') {
          $decoded = json_decode($body, true);
          $err = 'Error calling '.$response->getRequestMethod().' '.$response->getUrl();
          if ($decoded != null && isset($decoded['error']['message']) && isset($decoded['error']['code'])) {
              // if we're getting a json encoded error definition, use that instead of the raw response
        // body for improved readability
        $err .= ": ({$decoded['error']['code']}) {$decoded['error']['message']}";
          } else {
              $err .= ": ($code) $body";
          }
          throw new Google_ServiceException($err, $code, null, $decoded['error']['errors']);
      }

    // Only attempt to decode the response, if the response code wasn't (204) 'no content'
    if ($code != '204') {
        $decoded = json_decode($body, true);
        if ($decoded === null || $decoded === '') {
            throw new Google_ServiceException("Invalid json in service response: $body");
        }
    }

      return $decoded;
  }
  /**
   * Parse/expand request parameters and create a fully qualified
   * request uri.
   * @static
   * @param string $servicePath
   * @param string $restPath
   * @param array $params
   * @return string $requestUrl
   */
  public static function createRequestUri($servicePath, $restPath, $params)
  {
      $requestUrl = $servicePath.$restPath;
      $uriTemplateVars = array();
      $queryVars = array();
      foreach ($params as $paramName => $paramSpec) {
          // Discovery v1.0 puts the canonical location under the 'location' field.
      if (! isset($paramSpec['location'])) {
          $paramSpec['location'] = $paramSpec['restParameterType'];
      }
          if ($paramSpec['type'] == 'boolean') {
              $paramSpec['value'] = ($paramSpec['value']) ? 'true' : 'false';
          }
          if ($paramSpec['location'] == 'path') {
              $uriTemplateVars[$paramName] = $paramSpec['value'];
          } else {
              if (isset($paramSpec['repeated']) && is_array($paramSpec['value'])) {
                  foreach ($paramSpec['value'] as $value) {
                      $queryVars[] = $paramName.'='.rawurlencode($value);
                  }
              } else {
                  $queryVars[] = $paramName.'='.rawurlencode($paramSpec['value']);
              }
          }
      }
      if (count($uriTemplateVars)) {
          $uriTemplateParser = new URI_Template_Parser($requestUrl);
          $requestUrl = $uriTemplateParser->expand($uriTemplateVars);
      }
    //FIXME work around for the the uri template lib which url encodes
    // the @'s & confuses our servers.
    $requestUrl = str_replace('%40', '@', $requestUrl);
      if (count($queryVars)) {
          $requestUrl .= '?'.implode($queryVars, '&');
      }

      return $requestUrl;
  }
}
